[lvc-project] [Intel-wired-lan] [PATCH net-next v2 1/2] e1000: limit endianness conversion to boundary words

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On Behalf
> Of Agalakov Daniil
> Sent: Wednesday, March 25, 2026 4:16 PM
> To: Nguyen, Anthony L <anthony.l.nguyen at intel.com>
> Cc: Agalakov Daniil <ade at amicon.ru>; Kitszel, Przemyslaw
> <przemyslaw.kitszel at intel.com>; Andrew Lunn <andrew+netdev at lunn.ch>;
> David S. Miller <davem at davemloft.net>; Eric Dumazet
> <edumazet at google.com>; Jakub Kicinski <kuba at kernel.org>; Paolo Abeni
> <pabeni at redhat.com>; intel-wired-lan at lists.osuosl.org;
> netdev at vger.kernel.org; linux-kernel at vger.kernel.org; lvc-
> project at linuxtesting.org; Daniil Iskhakov <dish at amicon.ru>; Roman
> Razov <rrv at amicon.ru>
> Subject: [Intel-wired-lan] [PATCH net-next v2 1/2] e1000: limit
> endianness conversion to boundary words
> 
> [Why]
> In e1000_set_eeprom(), the eeprom_buff is allocated to hold a range of
> words. However, only the boundary words (the first and the last) are
> populated from the EEPROM if the write request is not word-aligned.
> The words in the middle of the buffer remain uninitialized because
> they are intended to be completely overwritten by the new data via
> memcpy().
> 
> The previous implementation had a loop that performed le16_to_cpus()
> on the entire buffer. This resulted in endianness conversion being
> performed on uninitialized memory for all interior words.
> 
> Fix this by converting the endianness only for the boundary words
> immediately after they are successfully read from the EEPROM.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Co-developed-by: Iskhakov Daniil <dish at amicon.ru>
> Signed-off-by: Iskhakov Daniil <dish at amicon.ru>
> Signed-off-by: Agalakov Daniil <ade at amicon.ru>
> ---
> v2:
>  - Split from the original bugfix series and targeted at 'net-text'.
>  - Removed the Fixes: tag; limiting the conversion scope is an
>    improvement to avoid unnecessary processing of uninitialized
> memory.
>  - Improved commit description for clarity.
> 
>  drivers/net/ethernet/intel/e1000/e1000_ethtool.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> index ab232b3fbbd0..38b1f91823ef 100644
> --- a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> +++ b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
> @@ -496,6 +496,10 @@ static int e1000_set_eeprom(struct net_device
> *netdev,
>  		 */
>  		ret_val = e1000_read_eeprom(hw, first_word, 1,
>  					    &eeprom_buff[0]);
> +
> +		/* Device's eeprom is always little-endian, word
> addressable */
> +		le16_to_cpus(&eeprom_buff[0]);
> +
>  		ptr++;
>  	}
>  	if (((eeprom->offset + eeprom->len) & 1) && (ret_val == 0)) {
> @@ -504,11 +508,10 @@ static int e1000_set_eeprom(struct net_device
> *netdev,
>  		 */
>  		ret_val = e1000_read_eeprom(hw, last_word, 1,
>  					    &eeprom_buff[last_word -
> first_word]);
> -	}
> 
> -	/* Device's eeprom is always little-endian, word addressable */
> -	for (i = 0; i < last_word - first_word + 1; i++)
> -		le16_to_cpus(&eeprom_buff[i]);
> +		/* Device's eeprom is always little-endian, word
> addressable */
> +		le16_to_cpus(&eeprom_buff[last_word - first_word]);
> +	}
> 
>  	memcpy(ptr, bytes, eeprom->len);
> 
> --
> 2.51.0

e1000e: limit endianness conversion to boundary words